Fluid-pressure brake.



W. v. TURNER.

FLUID PRESSURE BRAKE.

APPLICATION FILED MAR. 27, 1906.

Patented Feb. 2-3, 1915.

8 SHEETSFSHEET 1.

W. V. TURNER.

FLUID PRESSURE BRAKE. APPLICATION FILED HA1}. 27, 1906. I

' Patented Feb. 23, 1915.

W. V. TURNER.

FLUID PRESSURE BRAKE.

' APPLICATION F'ILED MAR.27,1906.

Patented Feb. 23, 1915.

7 Specification of Letters Patent.

FLUID-PRESSURE BRAKE.

Application filed March 27', 1906. Serial No. 308,310.

This invention relates to automatic air 1 brake systems for railway trains, and more particularly to the locomotive or engine brake equipment for such systems, one of the main objects being to provide an apparatus of this type, in which asingle engineers brake valve may be employed for controlling the automatic brakes of the engine and train, either conjointly or controlling the engine brakes independently of thetrain brakes, whereby the train brakes may be rc- 2o leased and recharged while holding the engine brakes applied, or the engine brakes may be released and applied as desired without afl'ectin'gthe in .n brakes. and regardless or' the position of the latter, that is, as to whether said train brakes are released or ap-- plied, the brake valve being provided with suitable ports and a sufiicientnumber of positions to produce these results.

r In my prior application, Serial No. 244,265, filed. Feb. 6, 19( )5, is disclosed an apparatus somewhat similar to mypresent improvement and having a single, engineers brake valve with suitable ports and posi= tions whereby the engine brakes may be applied and released independently of the train brakes provided the latter are off, but not if said train brakes are applied;

In order to be able to apply and release the engine brakes independently of the train brakes, both when said train brakes are re leased'and also when applied, it is important that the feed supply to the train brake pipe should be maintained when the train brakes are off and the engine brakes are being opera'ted independently, and it is also neces sary to prevent feeding the train brake pipe to raise the pressure therein while the train brakes are on and the engine brakes are being operated independently. as that would sit a release oi" the train brakes. An ap- -p ratus having all of these desirable functin and advantageous features is covered by my prior pending application, Serial No. 2871527, filed Nov. 15, 1905, in which two ini'l'ependeiitly operable brake valves are em.-

Patented Feb. 23, 19115..

ployed, the engineers brake valve for controlhng the automatic engine and train brake system, and an independent or straight air brake valve for controlling the engine brakes independently. In that construction the feed to the train brake pipe is controlled by the engineers brake valve, so that this supply is maintained when this valve is in running position with the train brakes released and the e ngine brakes are being operated by the independent brake valve; also, if the engineers brake valve is in lap position with the plie the train brake pip engine brakes with the When these functions are singlebrake valve or a train brakes ape pressure is not afi ected-by the independent operation of the separate valve. combined into a valve mechanism operated by a single handle, as in my present invention, it is necessary in the so-called straight air positions, or those positions of the valve controlling the engine brake independently, to maintain pipe pressure in order to the train brake prevent the same from being reduced on account of leakage.

According to my presen t improvement, I

employ a maintaining feed valve device, so controlled by the engineers brake valve, that in the straight air positions it opcrates to automatically In brake pipe pressure at wh tains in said pipe at the ti brake valve is turned to the aintain the train atever degree obme the engineers said independent positions for operating the engine brakes.

Thus, if the train brakes are off, and the automatic system fully charged, when the engine brakes are operated independently the train pipe pressure will be maintained charged at the normal degree of pressure, while ifthe train brakes have been previously applied and are on at this time of independent operation of the engine brakes,

the train pipe pressure will be maintained at whatever degree of reduction was made when said automatic'train brakes were applied. In this way, the sa me positions may be used at all times for operating the engine brakes independently, regardless of whether the train brakes are on or oil". Any suitable means may be employed to train pipe pressure in th positions of the engineers r maintaining the e straight air brake val-ve when the train brakes are off. and for preventing a feeding up of the train hese positlons when the pipe pressure in train brakes are applied. For this purposejl prefer to employ a maintaining feed'valve device, such as is covered in Patent No. 857,912 of myself and F. ll. Clark, dated June 25, 1907,

the-same being connected up to the'engineers brake valve according to my present improvements to give the desired results.

In said prior patent the maintaining feed valve device is so connected to the engineers brake valve as to operate automatically to maintain the train pipe pressure constant at any given degree of reduction when the .engineers brake valve is in lap position, While according to my present improvement it not only maintains the train pipe pressure constant in the lap position but also in the straight air positions mitted to the train pipe without a separate port for that purpose, and comprises a port or other means controlled by the engineersbraire valve in full release position for causing the feed valve to stand wide open regardless of the degree of pressure in the train pipe and thereby supply excess pressure from the main reservoir through the feed valve and thelsupplyport in the engineers brake valve as long as the same remains in full release position, but when turned to running position the train pipe pressure ,regulates the supply of fluid through the supply port of the engineers brake valve to the train pipe and limits the pressure to the desired maximum degree.

Another feature of my present invention relates to the so-called distributing valvedevice which controls the supply of airto the engine brake cylinders when operating either with the automatic system or with the direct independent system, as set forth in my two prior .applicati s, above referred to, one. obliect being to so are a more sensitive operation of the valve mechanism sub- 'ject to variations in train pipe pressure by the use of a small graduating valve having an independent movement with thepiston relativeto the main valvez and another object being to provide a higher degree of ing valve device, by the use of a differential piston for actuating the brace cylin-. ,der supply valve. I

In the accompanying drawings, Figure 1 1s a diagrammatic view showing in elevation a fluid pressure brake system embodying my improvements; Fig. 2 a similar diagrammatic view, on a larger scale, showing the engineers brake valve seat in plan, and

the maintaining feed valve and the distributingvalve devices in vertical section; Fig, 3 a vertical section through a portion of the engineers brake valve showing the rotary valve and equalizing piston; Fig. l a face view of the rotary valve of the engineers brake valve; Fig.5 a vertical section of the rotary valve on a larger scale, taken on the line XX of Fig. 4; and Figs. 6 to 14, inclusive, diagrams illustrating the various positions of the rotary valve of the engineers brake valve, the ports in the valve seat being indicated by the shaded portions, those in the face of the rotary valve by heavy lines, and the cavities in Said valve by dotted lines. 1 7

According to the construction shown in the drawings, the brake equipment comprises a main reservoir 15, connected by pipe 16 witlrthe distributing valve device 19 and to .the main valve 25 of the feed valve device, from which a pipe 2i leads to the port 38 and the rotary valve chamber of the engineers brake valve 17, which is provided with the usual equalizing piston 49 and chamber 48 communicating through passage 23 with equalizing reservoir 22, and is connected to the train brake pipe 18, which leads to the distributing valve device 19, and also extends through the train-to the car brake equipments comprising the usual triple valve 35, auxiliary reservoir 36, and brake cylinder 37.

The feed valve mechanism is preferably of the maintaining type,similar to that disclosed in the Turner and Clark Patent No.

857,912, before referred to, and comprises a nain valve with a regulating device 26 and chamber of the engineers brake valve. This space alsoco'rumunicates through passage 10 1 with die; iragm'chamber 94: having diaphragm 95 and adjustable spring 97 for operating the regulating 'valve 96. The feed passage also communicates with the chamber 99 on one side of the diaphragm 100,

which issubiect on its opposite side to the pressure of the maintaining chamber 98 and operates the small regulating valve 101, which at certain times controls the release of fluid from the piston chamber 92 through the passage 105. A small reservoir 31 may be connected with the maintaining chamber" to give the desired volume theret v For cooperating with the feed valve'mcchani sm and distributing valve device the seat of the engineers brake-valve may be provided with the fol owing ports, train pipe port 39 leading tothe train pipe 18, ports izing reservoir chamber,

mg chamber 98 ofthe having a piston A 1,12e,s1s la 41 and 44 communicating with the equalport 42 communicating with pipe 30 leading-to the maintainfeed valve mechanism, port 43 leading to the train pipe pas sage, port 46 communicating with pipe 29 leading to piston chamber 92, port 17 communicating with pipe 28 leading to the regulating valve 96 of the feed valve mechanism, port communicating by pipe 32 with the application chamber of the dis tributing valve device, and exhaust port 40 leading to the atmosphere.

In the rotary valve 50 is formed a main cavity 51 having port openings 53, 54, 58, 59, 60, 62 and 63 in the face, while the valve is also provided with through ports 52, and

57, and other small cavities 56 61, and 64 in the face of the valve.

For the purpose of controlling the supply and release of fluid to and from the engine brake cylinders, a distributing valve device similar to that disclosed in my prior application above mentioned may be employed, and this comprises a triple valve portion 67 operating. in chamber 66 in response to variations in train pipe pres sure to move a valve inchamber 68 to control the supply of fluidfrom the auxiliary chamber 69 to the application chamber 70, and a brake cylinder supply and release valve mechanism composed of supply valve pressure of the a 81 in chamber 80, and release valve 85 in chamber 84, both operated by stem 83 of a governing piston, which is subject to the pplication chamber on one side and of the brake cylinder on the other, the valve chamber 84 communicating di rectly with pipe 21leadin'g to the brake cylinders 20 of the engine or engine and tender.

According to one of the features of, my present impro'vement, the governing piston is formed of differential heads 78 and 79, the ormer being subject to the pressure of chamber 77, which communicates through port 71 with the application chamber and. forms a part thereof, and the latter being exposed on its opposite side to the'brakc cylinder pressure in valve chamber 84, the space between said piston heads being open to the atmosphere, if desired. In this manner any desired ratio between the pressures of the application chamber and the engine brake cylinders may be produced by forming the differential piston heads of suitable areas.

Another feature wherein the present structure is differentiated from, that of the former application, comprises the graduating valve 72 operated by the stem 71 of the triple piston 67 and having an independent movement relative to the main slide valve 73 for controlling the port 7 1 therein, whereby the valve is rendered more sensitive in its liowing through pipe 24 tary valve.

action. The main slide valve 73 is provided with a cavity 75 adapted to connect ports 71 and 76 when it is desired to release thev application chamber by the action of the triple valve, as on the second engine in double- 1-,; heading service, in which case the cock 33 may be turned to open port 7 (3 to the atmosphere.

The operation of my improved apparatus is as follows :With the engineers brake valve in running position, as indicated in Fig. 7, compressed. air from the main reservoir flows through pipe .16 to feed valve chamber-88, where it acts upon the piston and opens the main feed port 91, thence 3 i and port 38 to engineers brake valve chamber above-the to In' this position the ports 46 and 47 are connected by cavity 64, so that communication is established from piston 85 chamber 92 through pipes 29 and 28 to the regulating valve 96. As the pressure which then exists at the supply port 91 and in the regulating chamber 94 beneath the diaphragm 95 is less than the desired degree of maximum train pipe pressure for .which the spring 97 is adjusted,the valve 96 remains open, thereby releasing fluid, which leaks around the piston 90, to the atmosphere, so that the feed valve port 91 remains m5 open and air continues to flow through ports 52 and 39 of the engineers brake valve to the train brake pipe 18, where it operates to, charge the auxiliary reservoirs throughout the train in the usual way. Airalso flows through ports 55 and 41 to the equalizing reservoir and through ports 44, 43, cavity 56 and port 42 to pipe 30 and the maintaining chamber 98 and reservoir 31. Pressu e also rises at the same rate in chamber 99 on the opposite side of maintaining diaphragm 100,. being in communication with the feed pipe through port 104:,

The auxiliary chamber 69 may be charged from the train pipe through a feed 11mv groove around the triple piston 67 At the same time, the application chamber 70 IS in communication through port 71, pipe 32, ports 45, 59, cavity 51 and ports 53 and 40 with the atmosphere, so that the engine 1 brake cylinders 20 are released through pipe 21, chamber 84, and exhaust port 86. \Vhen the pressure supplied through the feed valve turned to service position, illustrated'in Fig. 13, thereby permitting a preliminary discharge of air-from theequalizing reservoir through ports. 41, 60, cavity 51, and ports 53 and 40 to thegexhaust At the same time, it

, willbe noticed that the maintaining reservoir is in communication with the equalizin reservoir through 30141 42, cavity 61 an discharge valve and reduce the train pipe pressure to the manner. a v

In the service andv lap positions-of,- the brake valve, the ports and fl'nre closed, so that the position of'the regulating valve 96, hasno effect upon the feed valve iston which is nowrontrolled by-the regu ating valve 101 operated by maintaining diaphragmlOO, J

'As'the port152 of the rotaryval veis'opento the train pipe port 39 in the lap position, train pipe pressure exists in pipe 24 and through portlOet in chamber 99 above dia-- phragm 100,-while the under side 'of said diaphragm is subject to thesealed pressure of themaintaining chamber.

same degree-in the 'usual The reduction in train pipe pressure operatesto apply the automatic train brakes] by'the action of the't'riple valves in the usual way. On the engine, the reduction in train pipe pressure causesthepiston 67 to move outward with the graduating valve 72, opening port 74 and then moving the mainslide valve '73" to register port 74 with port 71.

v .20. As the.

Air then flows from the pressure chamber 69 to "the-application chamber 70, charging the same to the desired degree, whereupon the pressure in the chamber 69 falls to an amount slightly less than the train pipe pressure, which then moves the piston and the graduating'valve 72 sufficiently to close the port 74. The pressure in application chamber 0 and chamber 7 7 acting on piston head 78 and-stem 83 moves the valve 85 to close exhaust port 86, and the valve 81 to'open port 82 and supply air to the valvechamber 84 and through ipe 21 to the'bralze cylinders brake cylinder ressure rises to a point such that the tot'a ressure on piston 79 equalsthat actingon' p1ston78 the spring 87 actuates the stemBB and-valve'81 1 to close the supply port 82. By means of the differential pistons '7 8 thud 7 9 a, higher degree of pressure will be secured" in the engine' brake cylinders than is produced'in the application chamber.

'Fig. 6, air is supplied through ports and 39 to :the train pipe when the increase in pressure causes theusual' action of the triple valves throughout the train to release the car brakes. his increase in train pipe pressure also moves the piston 67 with valves 72 and 73 to normal position and recharges the-auxiliary pressure chamber'69, but the engine brake is still held applied, since the port 45 which communicates through pipe 32 and ort 71 with the application chamber is stlll held closed. at the brake valve in release position. The result of, this is to cause a bunching of the train and prevent a surging ahead of'the locomotive at the time of releasing brakes. This feature is also present in' the apparatus disclosed in my prior-applications above mentioned... When the engineers brake valve is then turned to' running position, the air from the-application chamber is discharged to 'the atmos-' phere through. 45, '59, 53 and 40, and the brake cylinder pressureactm ,o'n piston 79 moves the valve 85 to open ex aust port 86, thereby releasing the air from the brake cylinders of the engine, or both engine and tender, if desired, to the atmosphere.

' When the brakes are applied and the engineers brake valve is-in lap position, with the port 52 open to train pipe port 39 and the feed valve controlled by the pressure scaled up in the maintaining chamber, as before described, it will be seen that, should there be any leakage from the train pi e tending to reduce t e pressure therein, t e

maintaining diaphragm will operate the:

regulatin valve 101 to open the'main feed valve suihcientl to supply all such leakage and maintain t etrain pipe pressure c0nstant at the given degree of reduction, and

to this extent the action of the present device is similar to that of prior application of Turner and Clark, above referred to. A

light spring 102 may be employed, if do I sired, to bear upon the diaphra assist the pressure of the maintaining chamber. 1

A novel and. important feature of the present apparatus comprises means, such as a port 63 1n the rotar valve, for opening communication from t e feed valve piston chamber 92 through pipe 29, port 46 and outlet ports 53 and 40, 1n the release position of the engineers brake valve, see Fig.

6, whereby the pressure is released from the back of piston 90 and the mainreservoir pressure in valve chamber 88 holds the feed port 91 wide open-and supplies air at the excess main reservoir pressure directly to the train pipe, as long as the engineers brake valve remains in this, position. By,

- eated between the main reservoir and the may be turned valve 96 is cut out engineers brake valve, and the advantages of the excess main reservoir pressure may be secured without an valve.

"If, when the brakes are applied,'both on the locomotive and throughout the train, it is desired to release the train brakes only and recharge, while holding the engine brakes applied, the engineers brake valve from lap to train release position, Fig. 8, in which the cavity 6-iconnects the ports 1-6 and 47, so that the feed valve is controlled by the diaphragm 95 and regulating valve 96, the same as in running position, and air flows from the feed valve through ports and 39 to the train pipe, releasing the triple valves on the cars and recharging the systemup to the normal degree for 97 of the feed valveis adjusted. But, at the same time, the engine brakes are held applied, since the port 45,

cates with the application chamber of the distributing valve device is held closed at the engineers brake valve.

brakes may then be released down, as desired, by turning the engineers brake valve to running position, as before described. I If, when the automatic brake is applied n the locomotive and train, it be desired to release the engine brakes independently The engine or graded and hold the train brakes applied, the brake valve may be turned from lap to the socalled straight air release position, Fig. 9, in'which the port 45 registers with port 58 in the rotary valve and the air from the application chamber of the distributing valve device is released to the atmosphere through cavity 51 and ports 53 and i0, so that the engine brakes are immediatelvreleased by the action of the piston 79 and exhaust valve 85, as before described. At the same time, the ports 46 and 4.7 are disconnected and closed, so that the regulating then controlled by the maintaining diaphragm 100, which is still subject to the pressure scaled up in the maintaining reservoir, since the port 42 communicating therewith remains closed and operates to maintain the train pipe pressure at the given degree of reduction in the same manner as when the brake valve was in lap position, without affecting the train brakes. The latter are therefore held applied while the engine brakes are released. If desired, the engine brakes may them be applied again independently without affecting the train brakes by turning the brake valve to straight air application position, Fig. 11, in which port 57 registers with port 45,

additional pipe con-- nection from the main reservolr to the brake which the spring which communithis may be done by turning and the feed valve is then turned to straight air' manner as when in lap position, since the main supply ports 52 in all of these positions of the valve. [he feed valve also furnishes the supply of air to the application chamber in the straight air position of the brake valve, since this drawing off of air from the brake valve chamber acts precisely the same as a leak from the train brake pipe, the pressure in which is maintained by the feedvalve at whatever degree was scaled up in the main taining reservoir. In the straight air lap position, also, thetrain pipe is in communication with the equalizing reservoir through ports 43 and 44 and cavity 56, so that these pressures remain equalized. It \villtherefore be seen that the engine brakes may be released andapplied or controlled as desired, independently of the train brakes, and while the latter are applied without in any manner allecting the train brakes. If all brakes are released at the time it is desired to apply and release or control the engine brakes independently, the'brake valve to its straight air positions in precisely the same manner before described, since at this time the train pipe with the equalizing reservoir and the maintaining reservoir are and 39 remain open substantially recharged to the normal degree, consequently this degree of pressure .is moved to its and the feed valve will operate to maintain this train pipe pressure constant, as before described. It will now be. evident that not only may the engine brakes and train brakes be controlled independently of each other, but that when en gine brakes are'being operated at the time that the train brakes are oil. the train pipe pressure is maintained against leakage, so that the ail-pressure throughout the train pipe and auxiliary reservoirs of the train will not become depleted, no matter how long the brake valve remains in the straight air positions; and :lso, that when the engine brakes are being operated independently at the time that the train brakes are train brakes, but the train pipe pressure is .then merely maintained constant at whatever degree previously obtained, so that the train brakes are not. affected. By this means, the same positions of the brake valve may be used for controlling the engine brakes independently of the train brakes, either when the train brakes are released or when they are applied, which is a great advantage.

In the emergency position of the lorake valve, as shown in Fig. 14, the large train pipe port 39 is open to theatmosphere through port 54, cavity 51 and ports 53 and 40,- while the equalizing reservoir is vented through ports 62 and 41, and the maintaining reservoir through ports 42 and 63, thereby producing a sudden reductionin train pipe pressure to produce quick-action of the triple valves throughout the train in the usual way. 1 'While I have described the maintaining feature as forming a part of the feed valve device, it will be obvious that it may be separately constructed, if desired, and also that the feed valve instead of being connected by pipes may be connected by cored passages in the casings of the engineers brake valve and feed valve, and may be located otherwise than shown in the drawings.

Having now described my invention, what I claim as new and desire to secure by Let: ters Patent is 1. An engine brake equipment, comprising a main reservoir, train brake pipe, and mechanism operating in response to variations in train pipe pressure to apply the engine brakes, and an engineers brake valve having positions with ports for'controlling the supply of air to and its release from the train pipe to operate the engine brakes and the automatic train brakes, and another position for releasing the engine brakes, with out afi'ecting the trainbrakes and for supplying air to the train pipe to compensate for leakage. V

2; An engine brake equipment, comprising a. main reservoir, train brake pipe, and mechanism operating in response to variations in train pipe pressure to apply the engine brakes, and an engineers brake valve having positions with ports for controlling the supply of air to and its release from the train pipe to operate the engine brakes and the automatic train brakes, and other straight air positions with means for applying and releasing the engine brakes independently of the application and releaseiof train brakes and for supplying air to the train pipe. 3. An engine brake equipment, comprising a main reservoirftrain brake pipe, and mechanism operatingin response to variations in train pipe pressure to apply the engine-brakes, and an engineers brake valve having positions with ports for controlling Y the supply of air to and its release from the train pipe to operate the engine brakes and the automatic train brakes, and straight air positions'for'applying and releasing the engine brakes independently of the train brakes whether the latter are on or off, and means for maintaining the train pipe pressure constant in the straight air positions-of the engineers brake valve. 5. In a fluid pressure brake, the combina tion with a main reservoir and train pipe, of a distributing valve mechanism comprising an application chamber and a valve governed by the pressure in said chamber for controlling the brake cylinder press-are, and an engineers brake valve having ports for controlling the supply of air to and its release from the train pipe for operatin the automatic train brakes, and another position for releasing air from. the application chamher when the train brakes are applied and without raising the train pipe pressure.

6. In a fluid pressure brake, the combinertion with a main reservoir and train pipe, of.

a distributing valve mechanism comprising an application chamber and a valve governed by the pressure in said chamber for controlling the brake cylinder pressure, and

an engineers brake valve having ports for controlling the supply of air to and its re lease from the train pipe for operating the automatic train brakes, other straight air positions with ports for supplying and releasing air to and from said a plication chamber, andmeans for maintaining the train pipe pressure constant in the straight air positions of the engineers brake valve.

7 Ina fluid pressure brake,"the combinationiwith amain reservoir, en neers brake valve, andtrain pipe, of a fee valve device for regulating the train pipe pressure, and

means operating when the engineers brake valve is in release position to hold the feed valve open and supply exc'ess main reservoir pressure to the train pipe. y

8. In a fluid pressure brake, the combination with a main reservoir, engineers brake valve, and train pipe, of'a feed valv'e device interposed between the meinreservoir and e11gii1eers lorake valvev and having a regulating device, the'eng neefs brake valve havtill valve, and

govern the iced valve in the nsane ing means for cutting out said regulating device in release position.

9. in a fluid pressure broke, the combination with main reservoir, enginecrs brake train pipe, oi a feed valve device comprising a rain valve, a piston foractte siting said val and r ulating valve operated by train pipe pres e for controlling the pressure on said acl, ting piston, the engineers brake valve having means for cut ting oil? communication from the feed valve piston chamber to the regulating valve in release position.

10. in a fluid pressure brake, the combine tion with a main reservoir, engineers brake valve, and train pipe, of a feed valve device comprising a main valve, a piston for actuating said valve, and. a regulating valve on erated by train pipe pressure for controlling the release of fluid un er pressure from the piston chamber, the engineers brake valve having ports for releasing fluid from said piston. chamber in release position.

11. In a fluid pressure brake, the combination with a main reservoir, train pipe, and

an engineers brake valve having automatic positions for controlling the train pipe pressure to operate the train brakes, and straight positions for controlling the engine brakes independently, of a valve mechanism adapted to maintain the train pipe pressure constant at any given degree of reduction, the brake valve having ports for causing the maintaining valve mechanism to operate in l the straight an: positions.

if .ln. a fluid pressure brake, the combination with a main reservoir, train pipe, and an engineers brake valve having automatic positions for controlling the tram pipe pressure to operate the train brakes, and straight air positions for controlling the engine brakes independently, of feed valve for Control ling the supply or air to the train pipe, at regulating valve device and a maintaining valve device for governing said feed valve, the engineers brake valve having" ports for cutting out the regulating, valve device and causing the maintaining valve device to straight air positions.

cylinder release valve 13. In a fluid pressure brake, a distributi g valve device comprising a valve for controlling the supply of air to the brake cylinder, an application chamber, a dili'ereutial piston for actuating said valve and having one head subject to the pressure of the application chamber and the other head subject to the brake cylinder pressure, and means for supplying air to said application chamber.

14. in a fluid pressure brake, a distribut- Ling valve device comprising a valve for controlling the supply of air to. the brake cylinder, an application chamber, a difierential piston for actuating said valve and having he larger head subject to the pressure, of

the application chamber and the smaller head to the brake cylinder pressure, a brake operated by said piston, and means for supplying and releasing air to and from said application chamber.

15. In a fluid pressure brake, a distributing valve devicecomprising an application chamber, valve mechanism operated by the opposing pressures of the application chamber andbrake cylinder for controlling the supply and release of air to and from the brake cylinder, a valve having a port for supplying air to said application chamber, a graduating valve for controlling said port, and a piston subject tothe train pipe pressure for operating said valve.

'16. An engine brake equipment comprising' a main reservoir, train pipe, and mechanisin operating in response to variations in train pipe pressure to eifect an applies? tion of the engine brakes, a single handled brake valve having-a straight air application position for controlling the engine brakes independently of the train brakes, and a valve mechanismior maintaining the train pipe pressure constant in the straight air application position of the brake valve.

In testimony whereof I have hereunto set my hand.

WALTER v. TURNER.

Witnesses:

R. .F. EMERY, J. B. MACDONALD. 

